SSC CGL 2024 Tier-I · 19 September 2024, Shift 2 · Quantitative Aptitude · Question 15 of 99

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 6 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Simplify the following expression.

(a)8
(b)16
(c)12
(d)4

Answer

Why

Correct — C. In the BODMAS order SSC uses, of is resolved before ÷ and ×.

The line is 25 ÷ 5 + 3 of 2 − 4 + 6 of 3 ÷ 2 − 8 + 4.
Take the two "of" products first:
3 of 2 = 6 and 6 of 3 = 18
Now: 25 ÷ 5 + 6 − 4 + 18 ÷ 2 − 8 + 4

Then the divisions:
25 ÷ 5 = 5 and 18 ÷ 2 = 9
Now: 5 + 6 − 4 + 9 − 8 + 4

Add and subtract strictly from the left:
5 + 6 = 11, − 4 = 7, + 9 = 16, − 8 = 8, + 4 = 12 → option (c).

Why the others are wrong

(a)
8 — A running total one term early. After 5 + 6 − 4 + 9 − 8 the chain stands at 8, and the line still carries a + 4 on the end.
(b)
16 — Another partial total. 5 + 6 − 4 + 9 = 16, which is where the working sits before − 8 and + 4 are applied. Option (b) stops two terms short.
(d)
4 — Below every value the chain ever takes. Worked from the left it passes through 5, 11, 7, 16 and 8 before ending at 12, so it never comes down as far as 4.

Concept

Of is the trap word. In the BODMAS convention these papers follow it behaves like a bracket — 3 of 2 is 3 × 2 = 6, cleared before any division touches it.

Here it matters at 6 of 3 ÷ 2. Resolving the of first gives 18 ÷ 2 = 9. Reading it as 6 of (3 ÷ 2) happens to give 9 as well, but the habit will cost you marks where the numbers do not divide evenly.

The tail of the line is the other half of the rule: addition and subtraction rank equally and are worked left to right, never all the plusses first.

Only the words "Simplify the following expression." are typed in the paper; the expression itself is an image, printed as a single line with no brackets anywhere in it.

Key facts

In BODMAS as SSC applies it, of is a bracket-strength multiplication and comes before ÷ and ×.
3 of 2 means 3 × 2 = 6.
Addition and subtraction share one rank and are evaluated from left to right.
25 ÷ 5 + 3 of 2 − 4 + 6 of 3 ÷ 2 − 8 + 4 reduces to 5 + 6 − 4 + 9 − 8 + 4 = 12.

Study next

BODMAS with nested brackets { } and [ ] sitting above ofWhy + and − are worked left to right rather than all additions firstSimplification chains that mix of with fractions and decimals

Common traps

Stopping at a running total, which is exactly what two of the printed options are
Doing every addition before every subtraction instead of moving left to right
Treating of as ordinary multiplication of equal rank, which is safe here but fails once brackets appear

SSC usually stacks brackets on top of the of in these items, so this one is the plain form of the rule.

13 Sep 2024, 09:00, Quant Q.15 runs [{70 − 60 ÷ 2 of 6} + (20 − 10) ÷ 10] + 600 ÷ 25 of (2 × 3) × (2 of 3) + 2 of 5, and 26 Sep 2024, 12:30, Quant Q.19 opens with (60 + 64 ÷ 4 of 4) — the same of-before-division decision, wrapped in brackets.

Related PYQs

No directly related past PYQ was found.